Formation of conductive MOF@Metal oxide micro-nano composites via facile self-assembly for high-performance supercapacitors

Abstract

Metal-organic frameworks (MOFs), which are promising electrode materials, have been explored for clean energy applications such as electrochemical energy storage. In this study, to enhance the electrical conductivity without decreasing ion transfer efficiency and to balance both activity and stability, we used metal oxides that can directly react with organic ligands and consequently produce their micro-nanocrystallized composites. Furthermore, we investigated the growth process by adjusting the reaction time and by determining the relationship between facet exposure and reaction time. Subsequently, we tested their electrochemical performance and demonstrated that specific facet exposure and small size are critical for achieving high capacitance. This reveals not only the influence of the reaction time on the morphology of conductive MOF composites and size but also the influence of morphology and size on the electrochemical performance.